Sports stadiums typically have bleacher or bench seats, rather than the individual seats found in theatres. Bleachers are standardly made of long, plank-shaped metal or plastic and older bleachers were formed of long wooden planks. These bleachers typically lack upright lumbar and thoracic supports, although some may include stiff, narrow boards as makeshift upright lumbar and thoracic supports. Patrons are often expected to sit for great lengths of time during an event, and they become uncomfortable because of the strain that can result to their upper and lower back. Bleacher planks are frequently also used as spectator walkways and steps through the stadium and patrons may slip on the bleacher itself or on another patron, which can cause injuries.
Permanently affixed outdoor amphitheater seats are known in the art, however these seats are designed to have a large clearance area which poses safety and comfort issues for the using patron and the surrounding patrons.
Portable stadium bleacher seats are known in the art and may be purchased and carried into the stadium by the patrons. The portable seats are pre-formed in dimensions which may not allow the patron enough open space between the other patrons around him or allow someone to walk by that patron or his/her seat safely, thereby causing a safety hazard.
A commonly used design is a foldable seat having a seat portion and an upright lumbar and thoracic support that is foldably connected. A hook or hooks may be located on the seat portion to engage the bleacher and (loosely) secure the seat in place to the plank. However, bleacher planks are of greatly varying thickness, so clip-on seats may be impractical. The seat portion may include a single hook, or two hooks, as set forth in U.S. Pat. Nos. 2,509,420 and 3,066,980. Some problems with these designs include the size of the hook. The hook openings must properly match the thickness of the bleacher to engage it safely or the seat will shift and slip during use, causing discomfort and possible injury to the patron. Portable seats may fit the bleachers of one stadium safely but are not adjustable to engage the bleachers of additional stadium and therefore do not provide multiple use and convenience to the patrons.
In addition, many portable seats lack adequately secured upright lumbar and thoracic supports, and these upright lumbar and thoracic supports may become lose in transit, or in use, especially in a crowded stadium with the feet of other patrons directly behind the upright lumbar and thoracic support or patrons walking by the upright lumbar and thoracic support of the seat. Some designs include a hook under the seat to engage a loop on the upright lumbar and thoracic support, or to engage the upright lumbar and thoracic support itself. However, those designs typically fail to securely hold the upright lumbar and thoracic support to the seat portion of the seat.